1. Field of the Invention
The present invention relates to an electric lamp with a base including a bulb capsule and a hold plate for holding the bulb capsule, in which the bulb capsule includes a pinch seal portion formed in one end portion of a glass bulb provided in the bulb capsule, and the hold plate includes two or more hold pieces, while the pinch seal portion of the bulb capsule can be connected with and held by the hold plate in such a manner that the pinch seal portion of the glass bulb of the bulb capsule is held by and between the hold pieces of the hold plate, and, in particular, to a technology which prevents the glass bulb of the bulb capsule against damage when or after the bulb capsule is held by the hold plate.
2. Related Art
FIGS. 6 and 7 show an example of a conventional electric lamp with a base.
In these figures, reference character a designates a bulb capsule of a halogen lamp. Reference character b stands for a glass bulb which is sealed in such a manner that one end of which is closed by a pinch seal portion c, with the other end thereof closed by an air exhaust portion d. Reference numeral e designates lead wires which are inserted through the pinch seal portion c, while the intermediate portions of the lead wires e are held by the pinch seal portion c. Here, filaments f are provided between the suitable leading ends of the lead wires e.
The pinch seal portion c is formed in a substantially flat shape and, on the two sides in the width direction of the pinch seal portion c, there are provided projecting strips g on the two side surfaces of the pinch seal portion c, so that the pinch seal portion c has a section of a substantially I shape. Further, in the substantially central portions of the two side surfaces of the pinch seal portion c, there are provided engaging projection sections h.
A hold plate i formed of a metal plate having spring elasticity has a substantially circular shape when it is viewed from top, and includes a peripheral edge which is bent stepwise.
The hold plate i includes a hold surface i. On the hold surface i, there are provided two pairs of intermediate hold pieces k and two pairs of side hold pieces l which are respectively formed by cutting and raising the corresponding portions of the hold surface i. The intermediate hold pieces k are formed opposed to each other, are respectively bent downwardly (in FIGS. 6 and 7, toward the lower edge side of the present drawing sheet) from the hold surface i, and are inclined in such a manner that the leading ends m of the mutually opposed hold pieces k are allowed to approach each other. On-the other hand, the side hold pieces l are similarly formed opposed to each other, are respectively bent upwardly from the hold surface i, and are inclined in such a manner that the leading ends n of the mutually opposed hold pieces l are allowed to approach each other.
Thus, the bulb capsule a is inserted into the hold plate i in such a manner that the pinch seal portion c of the bulb capsule a is inserted from above between the hold pieces k and l until, as can be seen in FIG. 7, the leading ends n of the hold pieces l contact the lower end portion of the glass bulb b, that is, the end portion o thereof on the pinch seal side. In this state (which is shown in FIG. 7), the intermediate hold pieces k are arranged in such a manner that the leading ends thereof m are located below the hold surface i and are elastically contacted with the side surface of the intermediate portion of the pinch seal portion c from both sides, while the leading ends thereof m are also engaged with the upper surfaces of the engaging projection sections h provided on the side surfaces of the pinch seal portion c.
On the other hand, the side hold pieces l are arranged in such a manner that the leading ends thereof n are located above the hold surface i, and are elastically contacted with the side surface of the intermediate portion of the pinch seal portion c from both sides and engaged with the pinch seal portion side end portion o of the glass bulb b, thereby preventing the bulb capsule a from being removed from the hold plate i.
However, in the above-mentioned conventional electric lamp with a base, when the bulb capsule a is held by the hold plate i, the sharp edges p of the leading ends n of the side hold pieces l are engaged with the pinch seal portion side end portion o of the glass bulb b, which causes the glass bulb b and pinch seal portion c to be damaged or cracked, thereby increasing the rate of production of poor products in an electric lamp manufacturing process.